1. The Technical Field
The present invention is directed generally to connection of stand-offs and other components to circuit boards, touch panels, and other substrates and components.
2. The Related Art
It can be desirable to mount additional components, substrates, and/or boards to a printed circuit board (“PCB”) or other substrate. It is known to use stand-offs with PCBs to mount additional components to the base PCB substrate. Traditionally, stand-offs have been press-fit into the PCB material, adhered to the PCB using adhesive or glue, or soldered to the PCB. Each of these methods has certain advantages and disadvantages.
For example, press-fit techniques, which rely on physical interference between the stand-off and the PCB substrate, can be implemented relatively easily and inexpensively. The strength of a press-fit connection, however, is a function of the interfering surface area between the stand-off and the PCB, which in turn is a function of the PCB thickness and the relevant stand-off dimension, for example, length. Thus, the strength of the connection between the stand-off and the PCB diminishes with decreasing PCB thickness. This phenomenon places a practical lower limit on the thickness of a PCB that is to incorporate a press-fit stand-off.
Adhesive or glue-based techniques rely on the strength of the adhesive or glue bonding the stand-off to the PCB and the surface area (usually very small) of the stand-off/substrate that the adhesive acts on. If the substrate includes a decorative layer, surface coating, or the like, these techniques may also rely on the integrity of the bond between such layers or coatings and the substrate. As such, adhesive or glue-based techniques may offer only limited strength. Also, adhesive strengths often decrease with increasing temperature. Accordingly, adhesive or glue-based techniques often are not suitable for use in high temperature applications.
Unlike the foregoing techniques, which can be used with stand-offs made of nearly any material, for example, plastic and metal, solder-based techniques generally employ metal stand-offs. Metal stand-offs can be more expensive to manufacture and use than stand-offs made of other materials, for example, plastic. Also, solder-based techniques often are unreliable because the strength of the solder connection is susceptible to variations in the soldering process and the size of the metal stand-off that typically would be used with such a technique because a metal stand-off acts as a heat sink when put through a reflow oven.
Traditional methods typically use rigid PCB materials (0.062″ and thicker), which generally are acceptable for flat applications. However, there are multiple benefits to using thinner PCB materials. For example, thinner PCB materials can more easily be formed to mate with other, corresponding three-dimensional substrates. Also, thinner PCB materials (or other substrate materials) often are less costly than thicker materials.